I am currently doing teacher practice with an ESOL class and had a few grammar questions if anyone can help. Firstly I have to teach a lesson with the following question: 'why does one speaker say 'the' greengrocers and the other 'a' greengrocers?' From the statements below:
(A) I'm going to the greengrocer's. Do you want anytjing?
(B) Excuse me, is there a greengrocer's near here?
I'm new to teaching English, and although i have a working definition in my head, i'd like to explain it simply but also with grammitical terminology. Also, i'm wondering exactly why we use 'a' and 'an', my understanding is that we use an before a word that begins with a vowel, such as apple, and a before everything else, although i'm not sure why, or if this is the exact reason. Any help would be very much appreaciated.